Hardness-testing device



Aug. 28, 1923.'

' R. BAUMANN EAEDNEss TESTING DEVICE MJ A', .//7 venten" EEE;

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Patented aeg. ze, i923.

unirse stares rareur orricel.

. RICHARD BAUMANN, or STUTTGART, GERMANY,

HARDNESS-TESVING DEVICE.

Application filed 'June .21, 1921,1 Serial No. 479,413.

To all 107mm t may concern: -1 Be 1t known that I, RICHARD BAUMANN, acitizen of the German Republic, and a resident of Stuttgart, Germany,have invented 'a predetermined position and with a predetermined springpressure so that it strikes a die and therewith forces the test ballinto the material to be tested. lln order that such an instrument shouldbeA satisfactory it is essential in the irst place that Yduring thestriking movement there shall be practically no action of Jrictionallforcesand tlierhammer should becontinuously central and be alwaysreleased in exactly the same manner. Secondly a predetermined equalamount of work must be done at each stroke, which on release of thehammer should be transmitted to the die, and thirdly strokes of dierentrstrength should be obtainable with one and the'same apparatus,according to the hardness and dimensions of the material to `be tested.Fourthlyit is, essential that test balls of different size maybeinsertedor interchanged withk other impression producing pieces.VFinally, the spring producing the stroke should be so adjustable withre-V spect as to its length and pressure that strokes of the sainestrength may be obtained.

-In accordance with this invention these results are obtained by theparticular arrangements hereinafter describedfor guiding and releasingthe weight. The hammer Vor weight is not externally guided and in factis guided solely by a central pin or rod along which it slides. Thecompression of the spring which acts on the'hammer or weight and causesit to accelerate at the moment of release is effected by holding thehammer -body by means of three cams uniformly varranged around theweight, while compressing the spring by pressing the testing device' onthe test material and the necessarily sudden release of the weight iseiected by the particular form of these camsiand of the shoulders on the.weight by meansof which said weight Vbears on the cams. As a resultblows of different strengthV may ber imparted vby forming theguidesleeve of -tlie testing device with openings at diii'erent heightsfor thecams which raise the weight and release r yit at a predeterminedposition, or the weight itself is formed with shoulders to b ear on thecamsV at dierent points or 'heights or otherk60 wise.

agrammatically thel openings in the guide sleeve of the device' atdiilernt, heights and positions.V Fig.Y 3 isv a View of a weightformedfwith shoulders." e l f' As shown, l denotes the ball l.which ispressed onv the material to: beztestedfand which dueto the force of theYweight leaves an impression in the material the .depth of c I whichimpression, iotherconditions are alike, depends on the hardness ofthe'matef rial, and thus formsfa vmeasure, of the hard- "5 ness of thematerial.` This ballflismounted inthe socket 3 which is screwed into theleasing Zot' the device,iandis held by-a die 4 l mounted tliereover soAthat ittcan be intenchanged with other members.y On the innerr 8O Ywall of the casing two cams yfo'rmed with Vblade springs 6 aresymmetrically arranged Y around the circumference. My vinvention is Ynotrestricted by the use olif two l cams. These cams 5 may project throughopenings 85 7 in the casing 2 and through corresponding openingsSv or 9on'an Vexternal guide sleeve 10 Vwhen said corresponding openings `8 or9 pass by these openings 7. The guide sleeve vl0 thusslides onthe'casing 2. In theinter- 90 mediate position ofthis' guide sleeve`Athe canis are pressed inwards.'` AA pinV or rod ll is centrally mountedwith respect toV sleeve l0 and it is secured' thereto. This p in or rodserves asa guide vfor the Vweight l2 which95 is otherwise free. Ahelical spring 13 is adjustably secured in the guide sleeve 10 l bymeans of ahead 14. The bottomV end l5 of the spring bears onashoulderron the weight'l2 and by raising this weight the 100V spring is4compressed accordingv to' the amount which the weight is raised. *The Apreferred embodiment of the invention weight 12 has downwardly inclinedannular shoulder 16 which on depression oi the guide sleeve contactswith the cams 5 so that when the testing device is placed on. the Yworkand the sleeve 10 depressed the weight 12 is held by these cams 5and thespring 13 compressed. l/Vhen the openings` 9 in thev guide sleeve passthe openings in the casing 2 the cams 5 pass through these openings themovement beingv assisted by their inclined portions parallel to the ders16. rhe weight is thus suddenly rey leased and the spring 13which hasbeen previouslycompressed to the desiredextent eX- pands downwardly and:drives the weight whose movementvis notr substantially retard'- f edby' friction andiiimparts a blow, correvsponding. to the compression .ofthe spring, to

the die and to the testing ball or the member proi'fidedvinA lieuthereof. As the openings v9.are provided at'diterent lateral positionsin the outer Iguide sleeved() the said sleeve can be `turned so thatvone oi these'openin'gs y rmoves earlier or later into the path Vof theopening fwhich-producesstronger or weaker blows. Y Y Y After the weighthas been released and the 'blow has been .struclr, the guide sleeve 10is movedoutwardly with respect to casing 2.A

. Instead of using different openings laterally arranged in the guidesleeve 1Q as shown in Fig. 2shoulders 16 are provided shown .in 3.

atdiilierent :heights on the weight itself as I It is then possible ltoobtain strolresof 'different strengthl according to the amountjby which'thevsleeve 10 is moved out of the'casing of the testing de-Y vice..Anfadditional advantage is secured inthatlinrorder to move the-testingdevice again. into striking position it is not neces- Y sary to moveYthe slee-ve 10 up with the ball, it

being sulicient vto withdraw the guide sleeve 10 viromvtheY casing`2independently Vof the position inthe space thereof. Furthermodyiiications may. be made so long as the arrangement for obtainingblows of different strength is retained. An internally threaded bushing17 haviiiga shoulder is fitted into the casing 1 0 and the 'top of thespring 13 is adjustably clamped between thebushing 17 and the externallythreaded head 14. LVThe rod 11 is connected tol the head 19 by thenut119. The member. 19 is kept in position bythe externally threaded cap18.

lf have described the parts herein by means .or reference numbers but li ish to make it Y.clear that wherever l 4,use such numerals, either inthen description or in the claims,

that I do not wish toV be limitedto the de- `tails ofthe embodimentsherein illustrated. The operation of my device is as follows: VTheapparatus is placed .upon the objectto be. tested, with theballl in'contact with the surface of thesaid object. The casing`10 is thendepressed. VWhen the openings 8 pass shoul- Y by the opening 7 ,theyforce thercams 5 inwardly against the resistance or the spring arm 6.-lence before the shoulder 16 ol the weight 12 has passed below the topsof the said cams 5, the said cams 5 have been moved so as to hold theweight 12 and pre-V vent the downward movement thereof. TheV downwardmovement of the casing 10 while the weight 12 is being held, causes thecompression otthe spring 13. 1When the openings 9 register with theOpenings 7, the spring arms 6, as well as the pressure of theinclinedshoulder 16 upon the inclined top of surface oi? the cams 5, cause thesecams 5 to move outwardly V'with great released. The weight 12now-'strikes the die 1ra sharp blow so as to press the ball v1v into thesurface of the object lwhich is being tested. Since the spring 13 `canbe adjust-V ably held by the parts before described, any one of the.shoulders 160iI the?A weight 12 shown in Fig. 8 canQbe causedto engagevwith the cams 5 soas' to provide'blows of greater or less strength.

VVVrapidity', so Vthat theyVY V,project through the openings l9 and theweight v12 is Having now particularly ydescribed the nature of myinvention, vwhat I: claim as newY and desire to secure by LettersyPatent of the United States is: f f Y 1. VIn an apparatus fortesti-ngthe hardness ot materials a combina-tion. of ak weight and a springlcooperating therewith, means for moving the said spring soV as ,tocompress it, and means Jfor simultaneously holding Vvthe weicht so as toprevent the movement thereof yithe action of theV saidA spring, and

means adapted to automatically causeV the release lof the said weightwhen. compression of the spring Ais at'ai'predetermined limit. i Y

2. Inl an apparatus for testing the ihard;- ness or materialsthe*conibination.v of the casing 2,.a' sleeve `1Oslidable thereon, :theweightl 12 and the spring 13Av connected'. to

Vthe casing 10', and holding means located inv the casing 2 and` adaptedto hold .the weight 12 while the casingylis beingV moved to compress thespring 13 and means adapted -to automaticallyr cause the .release of thethe shoulder 16 adapted to beyengaged by the Y cams 5, the said casing10 alsoA having the openings 9" therein.

4. An apparatus according to claim 3 iiiv which the spring 13 isadjustably held in the surface of vthe cams 5 being inclined to thecasing 1Q. said spring arms 6.

5. An apparatus according to claim 3 in In testimony whereof I affix mysignature Which the Weight 12 has a plurality of in presence of twoWitnesses.4

` 5 shoulders 16. RICHARD BAUMANN 6. An apparatus according to claim 3in Witnesses: v. which the cams 5 are mounted on spring FRIEDRICHENNLER,

arms 6, the shoulder 16 and the adjacent EMILIE Zum.

